Arocket sled that was initially at rest reaches a final speed of +30.0 m/s over a displacement of +45.0 m what is the acceleration of the slide show your work

-- The sled's average speed was     (1/2) (zero + 30 m/s)  =  15 m/s .

-- In order to cover 45 meters at an average speed of 15 m/s,
you have to travel for 

                     (45m / 15m/s) = 3 seconds.

-- So the sled accelerated from zero to 30 m/s in 3 seconds.

Its acceleration was  (30 m/s) / (3s)  =  10 m/s²

That's just about equal to the acceleration of gravity.

So the rider felt his own weight pulling him down into the seat,
as always, but there was also his own weight pulling him straight
back into the seat. 

The net effect of what he felt during the shot was  a single force of
41% MORE than his weight, pulling him down into the seat at a 45° angle